Method of and means for stabilizing refrigerants



June 16,- 1931; R. w. DAVENPORT METHOD OF AND MEANS FOR STABILIZINGREFRIGERAN'IS Fil ed June 17, 1926 INVENTOR. Ransom l V. DHI/ HP Y ATTORNEY.

Patentecl June 1931 t UNITED STATES PATENT OFFICE EANSOM W. DAV 'ENPORTOF DETROIT, MICHIGAN, ASSIGNORTO CHICAGO PNEUMATIC TOOL COMPANY, OF NEW,YORK, N. Y., A CORPORATION OF NEW J'IELR/SEY' METHOD OF AND FORSTABILIZING BEFRIGER AN'TS Applicatioii filed June 17,

I Thisliiiventionirelates to heat transforming systems and particularlyto the stabiliz- I ing ofthe working substances by which thethermodynamic effects are produced. The

invention'includes both a method and the I means by whichthe method ispracticed.

It has been observed thatfew if any work- 1 ing substances known or usedas refrigerants remain permanently unaltered during long periods ofoperation.- Even-non-electrolytes such as carbon tetrachloride,methylene chloride, the methyl and ethyl chlorides, etc. tend tohydrolyze intime due to the presence of traces of moisture, and toliberate traces of chlorine which may attack metals. It has beensuggestedto place in contact with the vapor of such refrigerantshygroscopic substances such as calcium chloride which are supposed todry the vapor and the liquid which results from the condensation of thevapor to a point which should prevent hydrolysis. I have found suchmethods unsatisfactory since with sufficient hydroscopic materialpresent to dry the vap'or enough of it passes with the vapor throughoutthe system to deposit a film of water moist material on the metal partsand accelerate rather than prevent corrosive effects.

Among the objects ofthe invention are to inhibit decomposition ofworking substances, to'prevent harmful effects from slight decompositionof such substances, to devise suitable means for accomplishing the aboveobjects, and in general to improve prior methods and apparatus. Otherobjects will be apparent from the detailed description which follows:

Instead of attempting to dry the refrigerant in situ as heretoforeproposed, my invention consists in starting with the refrigerant as dryas possible and then preventin decomposition or the harmful effects ofsuc action by my improved method which comprises acting upon therefrigerant while in liquid state so as to prevent the formation ofhydroxyl and to neutralize any acids which may form. To this end basicoxides such as calcium oxide (CaO) barium oxide, magnesium oxide, etc.may be used, also the corresponding hydroxides,.such as calciumhydroxide (Ca-OH), etc, Suitable means are 1926. Serial 1%; 116,512.

provided for bringing such substances into.

direct contact with some or all of the liquid bodies of the workingsubstance in the system. V

In order to illustrate the invention and the manner of its operation oneconcrete embodiment thereof is shown the accompanying drawings, inwhich:

Fig. 1 is a somewhat diagrammatic view of a refrlgerating system,certain of the parts of which are partly cut away or shown in sectionFig. 2 is a side elevational view on an enlarged'scale of a containerfor the moisture absorbing or acid neutralizing material; and

Fig. 3 is an end elevational view of the container shown in Fig. 2.

The heat transforming system indicated diagrammatically in Fig. 1 is ofthe closed cycle type comprising an evaporator or refrigerating element4 (disposed in a suitable chamber or refrigerator A), a pump orcompressor 5 withdrawing vapor from the evaporator 4 through a pipe 6and discharging the vapor at a higher temperature and pressure through apipe 7 into a condenser 8 where heat is extracted from the circulatedworking substance through a cooling medium which may be either air orwater, the condenser discharging into a chamber 9 in which thecondensate is collected, whence extends a conduit 10 which dischargesinto evaporator 4 through a suitable throttling member or expansiondevice 11. The working substance occurs inliquid form particularlyinevaporator 4 and in chamber 9. The working substance may be a liquidhaving a low boiling point of the type used in conventional systemsoperating on the Clausius-Rankine cycle, such as ammoniaor sulphurdioxide, or physical mixture of a volatile liquid and a gassubstantially inert to and insoluble in the liquid and in its vapor asdisclosed and claimed in my copending application, Serial No. 603,998,filed November 29th, 1922, operating in accordance with the processdisclosed in my copending appli cation Serial No.. 15,172, filed March12, 1925, or a lubricating refrigerant of the type disclosed in mycopending application Serial No. 60,311, filed October 3, 1925,operating in accordance with the processes set forth in my copendingapplications Serial No. 85,580, filed February 2,1926 and Serial No.88,164, filed February 15, 1926. The invention particularly relates,however, to Working substances having as their major component anon-electrolyte such as carbon tetrachloride, methylene chloride, themethyl and ethyl chlorides comprising the substances known aschlorinated methyl and chlorinated ethyl derivatives.

In accordance with my improved process,

the working substance is maintained in a stable condition and theharmful effects of decomposition are avoided by bringing the liquidrefrigerant into contact with suitable material for absorbing moistureand for neutralizing any acids which may form as a result of thetendency on the part of the refrigerant to hydrolize. To this endsuitable chemicals which are strongly alkaline and which have anafiinity for free moisture are utilized. Compounds suitable for thispurpose are the basic oxides, such as the oxidesof calcium, barium,magnesium, etc., also the hydroxides, resulting from the combinationtherewith of water in either its liquid or vapor state. A preferred wayto effect contact of the liquid refrigerant with such compounds is toimmerse the latter in the liquid refrigerant.-

This is best accomplished by placing the stabilizing material. in asuitable container having perforated walls, or preferably made entirelyof reticulated material of fine mesh. Figs. 2 and 3 illustrate acontainer 12 of this kind which is shown as cylindrical in form but maybe of any other desired shape and arranged to contain lumps 13 of thestabilizing material, such as calcium oxide (CaO).

Containers 12 may be inserted in the heat transforming system whereverthe working substance occurs in liquid form. In Fig. 1 such containersare disclosed as immersed in the liquid in evaporator member 4 and inthe liquid in chamber 9. Since there is more or less dilution of theworking substance by lubricant from the lubricating system and of thelubricant by refrigerant from the refrigerating system, it is also wellto place a container 12 with stabilizing material therein in thelubricant body. In Fig. 1, such a container is shown as immersed in. thesump of the crank case 5a of compressor 5. When lubricating refrigerantsare utilized the evaporator or refrigerating element 4 may have a.concentrating chamber 4a in which a body.

of the lubricating refrigerant gathers and one of the containers 12 forthe stabilizing material is preferably placed therein.

In the system shown "the working sub-c stance or refrigerant may have asits volatile li uid component, for example, methylene c oride and as itsgaseous component air.

'droxide.

The lubricant in the sump of compressor 5 may be a heavy oil or a thingrease having a paraflin base and the lumps of stabilizin material 13may be substantially pure and dry calcium oxide. Starting with themethylene chloride in evaporator 4 the vapor of the same together withthe air in the evaporator is drawn off by compressor 5 and dischargedinto condenser 8 where the vapor is liquefied and collects in chamber 9whence it passes through pipe 10 and expansion valve 11 back into theevaporator. In the form shown in Fig. 1, free moisture is removed fromthe working substance so as to maintain it in a substantially dry andstable condition at any desired number of spaced points, as in chambers4a and 9, respectively. Any lubricant which works over into therefrigerating system is also maintained in a substantially dry andstable condition by the action of the calcium oxide in container 12 inthe sump of the compressor. The combining of moisture with the calciumoxide produces calcium hydroxide (CaOH). Any acid which may result fromdecomposition of either the liquid refrigerant or of the lubricant willbe promptly neutralized through the action of the strongly basic calciumoxide or its hy- Thus if chlorine is liberated from methylene chloride,it will combine with the calcium oxide to form calcium chloride (CaClThe quantity and area of stabilizing material should be sufiicient tocause the law of mass action to operatethat is, there should be a largeexcess of basic material over that theoretically calculated to completethe reactions indicated. .When this is done the inhibitin effect of themethod is more complete. Tfie containers 12 are by preference formed ofmetal screen cloth of fine mesh to retain and confine the chemicalenclosed thereby.

From the above it will be apparent that the method of stabilizingworking substances herein disclosed operates through removing Ill) allfree moisture from both the circulated working substance and from anyother substance which may be'mingled therewith by intent or leakage andby promptly neutralizing all acid products of decomposition, that theeffects sought are readilyobtained by placing suitable chemicalmaterials in contact with the liquid working substance, and

that the enclosing of such chemicals in suitable containers prevents thedissipating of the chemicals through the system and facilitates therenewal of the active ingredients.

While but one form of the invention has been herein shown and describedit is to be understood that the invention is not limited to the specificdetails thereof but covers all changes, modificaitons, and adaptationswithv in the scope ofthe appended claims.

I claim as my invention: 1. In a heat transforming system involvrea'ctinwith water, the method of inhibiting the change of state of a liqiud'capable of ing sai .reaction which consists in repeatedly bringing saidliquid into contact with a substance adapted to supply hydroxyl ionsthereto. 7,

2. The method ofgstabilizing refrigerants of the chlorinated'hydrocarbon type which comprises bringii'ig'the liquid refrigerantrepeatedly into contact with a basic oxide.

3. In a heatztransforming system utilizing methylene,{chloride as theworking substance, the method of maintaining the latter in stablecondition which comprises repeatedly bringing the working substance inliquid state into contact with a basic oxide.

4. The. method of stabilizing refrigerants of the chlorinatedhydrocarbon type which comprises bringing the liquid refrigerantrepeatedly into contact with substantially pure and dry calcium oxide.

5. In a heat transforming system utilizing methylene chloride as theworking substance, the method of maintaining the latter in stablecondition which comprises repeatedly bringing the working substance inliquid state into contact withsubstantially pure and dry calcium oxide.

6. In the method of producing heat transforming effects by circulatingin a closed cycle a working substance which occurs in liquid and invapor states in various parts of the cycle, that step in themethod-which comprises subjecting the working substance while in liquidstate to the action of a basic oxide to extract moisture from theworking substance. V I

7 In the method Tof producing heat transforming effects by circulatingin, a closed cycle aworking substance which occurs in liquid and invapor states'in various parts of the cycle, that step in the-methodwhich comprises subjecting the' working substance while in liquid stateto the action of a. basic hydroxide in order to neutralize any acidresulting from decomposition of the.working substance.

- 8. In a mechanically operated heat transforming system of the closedcycle type uti lizing a working substance which occurs in liquid and invapor states in various parts of the system, means for removing moisturefrom the liquid working substance comprising a hollow member immersedtherein, said member having a perforate wall ,and containing a basicoxide.

9. In a mechanically operated heat trans forming system of. the closedcycle type utilizing a Working substance which occurs in liquid and invapor states in various parts of the system, and means repeatedlyeffecting contact of the liquid workingsubstance with material having anafiinity for water thereby to dry said-working substance said meanscomprising a series of perforated containers 10. In a mechanicallyoperated refrigerat ing system of the closed cycle type utilizing avolatile liquid as the refrigerant and hav-' ing chambers in which apart of the refrigerantgathers in liquid form, and means disposed insaid chambers for extracting moisture from said lijquid refrigerant andfor neutralizing. acids resul't'ing from decomposition of therefrigerant, said means comprising perforated containers inclosing achemi cal substance adapted to supply hydroxyl 1ons.

11. in a mechanically operated refrigerating system of the closed cycletype utilizing a volatile liquid as the refrigerant and having alubricating system containing lubricant, and means comprising containersof reticulated material disposing moisture absorbing and acidneutralizing material in contact with the liquid refrigerant and .withthe-luerant and the lubricant.

12; A closed cycle refrigerating system having acompressor, anevaporator, and a condenser, said evaporator containing liquidrefrigerant, and a container immersed in the liquid refrigerant in oneof said elements and enclosing a basic oxide for maintaining therefrigerant in a substantially dry and stable condition.

13. A closed cycle refrigerating system comprising an evaporatorcontaining liquid refrigerant, a compressor, said compressor withdrawingvaporized refrigerant from said evaporator, a condenser. into which saidcompressor discharges, an expansion device between said condenser andsaid evaporator,'a chamber for condensed refrigerant between saidcondenserand said device, and containers with stabilizing 'chemicalstherein immersed in the liquid insaid evaporator. and said chamber. i f

14. A closed cycle refrigerating system bricant in order to stabilizeboth the refrigcomprising an evaporator containing liquid refrigerant, acompressor, said compressor wlthdrawing vaporized refr gerant from saidevaporator, a condenser into which said compressor discharges, anexpansion device between said condenser and said evaporator,

: a chamber for condensed refrigerant between said condenser and saiddevice, said compressaid refrigerating and of said lubricating systemsto mantain both the lubricantand the refrigerant in stable condition.

15. In a mechanically operated refrigerating system having heattransforming means and a compressor provided with a lubricating v systemfor lubricating the parts thereof,

means disposing moisture absorbing and acid neutralizing material incontact with the lu bricant to stabilize the same.

16. In a mechanically operated refrigerating system having heattransforming ele- L3 ments and including a compressor having a sumpcontaining lubricant, means subjectlng said lubricant to the action of abasic oxide to maintain the same in stable condition.

17. In a mechanically operated refrigerating system having heattransforming means and includin a compressor having a sump containinglulmican't, a container with one or more perforated walls in said sump,said container having a substance therein adapted to supply hydroxylions to said lubricant.

18. In a mechanically operated refrigerating system having heattransforming means, a compressor having a sump containing lubricant, anda reticulated container 29 having calcium oxide therein, said containerbeing disposed in said sump.

Signed by me at Detroit, Wayne County, Michigan, this 14th day of June,1926.

RANSOM W. DAVENPORT.

